Because of the constraints of space in a dispenser used for dispensing cups, the dimensions of the components making up the dispenser must be minimized both as to size and number. Additionally, the movements of the components must be minimized.
One such dispenser comprises a plurality of cams spaced about a first axis (coaxial with the axis of the stack of cups) and drive means for rotating the cams together, each about an associated axis parallel to the first axis. A connector, for example, a gear carrying a handle, connects the cams to the drive means for rotating the cams.
Each of the cams has a cam face which cam face is a helix about its axis and is arranged to engage the rim of the end cup of a stack of cups located in the dispenser so that rotation of the handle through an angle of about 10 degrees, rotates the cams in one direction pushing the end cup away from the remainder of the stack dispensing the cup. The handle is then returned through the same arc to its initial position readying the cam for dispensing the next cup.
Where such dispenser has been tried for use to dispense foam cups, the dispenser of a construction as used to dispense conventional paper or thermofoamed plastic cups is not satisfactory.
Particularly, the rotation of the handle through the small arc (about 10 degrees) must be sufficient to cause the foam cup to be dispensed. Therefore, the helical angle of the cam face of the cam (which cam face is a helix about the cam's axis) must be such as to eject the engaged foam cup. If the helical angle of the dispensing cam face is too steep, the foam cup will be crushed. If the helical angle is too shallow, the resultant structure of the cam would be too large for the dispenser size required.
Conventionally the dispensing cam face is downwardly facing, and in the direction of any diameter, is normal to the axis of rotation of the cam. This disposition of the cam face however, is not satisfactory for use in dispensing foam cups. Particularly, this cam face does not provide a satisfactory dispensing action, tending to dig into the rim of the cup and scoring the rim, by a point contact between the cup rim and cam face when the cam face engages the rim, seriously damaging the cup.
It is thought that for minimizing scoring, contact of the cam face and the rim of the cup must be maximized. In this regard, the optimum shape of the cam face would be that of the rim of the cup it would be engaging (curved). However, the manufacture of such curved face on the cam would be very difficult to achieve--the die could not be separated from the injection moulded part, undercutting the curve in the cam face, damaging it.
It is therefore an object of this invention to provide a cam profile which provides a more satisfactory dispensing action and minimizes damage to the rim of a cup being dispensed.
Further and other objects of this invention will be realized by those skilled in the art from the following summary of the invention and detailed description of an embodiment.